Larval fish weaning (Chapter 3)

Weaning between live feed and inert diets in fish larvae is a critical phase during fish development since it is often accompanied by increased mortality and reduced growth. On the other hand, determination of the best protocol for a target species is considered a bottleneck for the success of the production cycle of hatcheries. This chapter describes the role of main factors involved in weaning process. One of the basic principles for the success of weaning is the correct evaluation of the time at which larvae can be fully fed a formulated inert diet. Different duration of weaning period can influence growth and/or survival. Technical aspects of the weaning management play a decisive role in order to maximize the efficiency of transition from live food to inert diets. The availability of diets suitable to the nutritional and feeding requirements of larvae primarily influences the weaning results. Success of a microdiet for larvae depends on many factors. For example, particle sizes, sedimentation rate or attractability are key characteristics for feeding at early developmental stages, at least as much important as their nutritional composition. In this regard, the availability of improved commercial microdiets allows considering early weaning as a new tool for further decreasing live feed usage. Recent studies, especially on marine species, are presented and discussed.